crawford



- OCt. 7, 1952 C, CRAWFORD y 2,613,145

APPARATUS FOR PRODUCING SYNTHESIS GAS lFiled Deo. 30, 1948 I N V EN TOR.

C/afafzre Z. Pan/f/a/d.

P t t d 1 aene Oct 7 952 if (STATES PATENT' OFFICE y y...rirrrlmurus''Foarecocente:SYNTHESIS 'GAS'.

Clarence L. .'Crawford; Plum'. Township, Allegheny' ration of. Delaware'Thisflinvention relatestofan'apparatusiorcan rying out reactions atadvanced temperatures-Jano superatmospheric pressures. More particularly"the :invention: relatesto :an apparatus; iorifproor; conversionzone. ir..vvliich3a;k High-temperature 1.01am. (crue-#196).

.reactlonis carriedout,to ac'oolingfzone.4 More.- 'orenz the; apparatus-comprsesfa compact and .efcient; arrangement: of; the,- fseveralelements required tu operate @,procjess of :generating syn;-

educingr-aatgasf.comprising.hydrogen; andrcarbon 5 thesis: gas.,monox'dali.. 1..' aesyntnesisiaas byfpartiallylreact.- The. apparatusrof the? invention includes an -ing .hydrocarbon-smith., oxygen:atteler/.lated .temelongated conversion tube. having heat retentivezperatures mdfsuneratmosphericpressures, Wallsfandagasrquenchcoolercomprising a plu- .A process-'Finn' the production of. Fischer;-rality :oiznarrow .heatexchangetubes terminatingTropsch;synthesisgasncomprisesa introducing :a l0 in. .upper zandlowertube sheets, thetubesibeing :mixturezofztnatural gasfzand zoxygen.intonaA con;- disposed? in v.parallel arrangement' and'fsurroundedversion; `zone; which .:c'onifersion temperatures by- .a chamber. foraluidrheat exchange medium', .of `tlie:order: of; :1800?"120 28.69 Eiand.' pressures allA containedifin. a 'single pressure-tight vessel.zoitlreforderruf lO.rtcolipoundslpersquareinch The gas quench cooler is.positioned aroundl the .acemantaineds The composition. of;t'lievclnarge l5 conversiomtube. Conduits.arefprovidedleading.mixtureris sucligeas. toyproduceuponconversion from ythe conversiontube to. the gas quench -fapminture-xof conversion products, comprising0001er.k `Conversion .gaSeSflleSSin One? direction desirable proportionsof: carbon. monoxide and threiieh the `Conversion tube', through. theC011- .fnydroeen randrtofevolve. sufficient heat. tomainduits'and-:inthe otherl direction. throughzther heat .tain-r the conversionitube:v at`the.:coni/ters',lon tem- 20 eehallgef tubes; peyamweg y Tlienyentionwill' be. .understood by :reference The conversion Vproducts; :initiallyformed are to theaecompanrne drawing, hereby mada-a,notin.thermodynamic:equilibriumat-theconver- DelOf 'this Speeee'omIWheh Figure' 1r vS'feL .sionv temperature and.. therefore.V the;conversion Vertice-1 SeetOnalveW of ian apparatus embdyingzone.f.shouldf-be:.:sufciently long `toprovi'de.an 25 the.rinvention.aldFigure. 2i`S aCI-OSS-Setienal equilibrium'zonewhereintheproductsarefmaixn View takenelOng'the lines A-A 0f Figure 1. tainedatan elevatedequilibrium temperature The" apparatus 'dSClOSed-n the drawing conn.above 170e" fr'. untiithermoeynamic equilibrium siste of.apreSsure-'teht vessel- 'fc'ontainine an is substantiallyestablished.The;A equilibrium elongated open 'conversion tube 6, :and a quenchcompositionfat this temperature lis the --desired 30 cooler ATwloicbsurroundsthe ycorwersion tube 6. composition. .Howeven `since theferiuilibrium The. vessel 51 is of steel,is.partially.insulatedwith`composition varies-withltemperatura the actual bottom insulating bricksSvand top 'insulating composition uiouldchaneetowardfa.new equilib.-`bricks 9, andv containsan outlet Ifi leading from ium compositionatsa-.newtemperature ifallowed tbe top ofthevessel. The conversion tube.'6 is .sufficient-.time To stabilize the desired compo,- 35 centeredwithin vessel 5 and is formed of a steel .sitionandlobtainsyntbesisgas-.under conditions cylinder lf2 containing heatlretentiveinsulating desirable.iur,.introductioninto `a synthesisl conbri'cks`if3',.;forming anannular heat retentive Wallvertersystemfftheinixtureattheconversionitemf le', and bottonrinsulatingbricks i8. The con- .perature smmdfbeimmedatei-y and-substantiallyversion tube isprovidec with radiaiiniets in the ,instantaneously cooledorquencheclto a substan.- 4G 'form .ofi-Ong nozzles .m .at the topthereof which tially unreactive temperature, preferably 'a tem,- extendWithout vessel 5. The nozzles i6 are fed peraturel of .below..1300 byfanupper oxygen manifold I l" Vand Aa lowerA nat* (meer theimportant.problems inyolvedin `ural"'gaszrnanifold t8. These manifolds aresuppracticinga process othisftype is tliatof-avoidplied by thevalvedflines shown on `-Figure 2. ing any substantial lOSsobeat from theconn 45 Commits` lewhichlea'd from the interior of the version Zone orproducts prior to the time the con-versiontube to an annularspa'oe orlchamber products are subjected to substantially instanta- 121i areformed-.byarranging heat'retentvel-bricks neous cooling. It is essentialthattbe cooling I3 to form apertures in the bottom of wall. I4 deviceemployed be closely adjacent to. the exit below the bottom of' steelcylinder I2.. The of the conversion tube to avoid heat losses in 50chamber 22.!v is formed-by tlfx'eflowerl portion of transferring theproducts from the tube to the zrefractory Wall. I'll,."the.^\vaterfWall22,` 'bottom cooling device since slow loss of heat prior to `insulating'bricks'. 3,'andt'thei lower tube sbeet'Zi; the: rapid cooling wouldproduce undesirable fof quench.l cooler. 1.V The quench cooler isvchanges.;inA gas composition., This problem prearranged as an annulusaround'ithe cylinderv I2 sentsa. .material difficulties` 1in;.preventing heat 55 Vand Aconsists l.of :a pluralitywofz'narrow steelgas transfenzparticularly transferrbyfradiation:from 'cooling` tubes.i241. positionedl in `parallel arrange- .onel zoneito. the other.. ment`'between the.- :lower- "tube sheet 23 and. an "The, apparatus, ofthepresent'- inventionfproupperitube lsheet 26; A chamber .2:1 adaptedto vdeseneective solution. ofizthe' problem vo prec'ontainl'acoolingj-mediium. such Sas Water "sur- Ventingltne transfer, .oft heatfrom the 'reaction 60 roundine'thevtubes'2f4ris formed by thei=upperand3 wall 28 of vessel 5. The cooling medium is introduced through inlet 29and withdrawn through outlet 3|.

The operation of the apparatus will be described in connection with aprocess for the production of synthesis gas. A mixture of natural gasand oxygen at an elevated temperature of about 1000 F. and a pressure ofabout 300 pounds per square inch is formed in nozzles I6 and introducedinto conversion tube 6. The conversion tube is maintained at atemperature of about 2500 F. and a pressure of about 300 pounds persquare inch, this temperature being obtained by the coni version ofprevious increments of the natural gas and oxygen mixture. The enteringmixture is raised rapidly to its conversion temperature and is convertedto conversion products comprising carbon monoxide, hydrogen, carbondioxide and steam. These conversion products move downwardly inconversion tube 6 at a rate such that on reaching the bottom of thetube, they are of substantially equilibrium composition at theconversion temperature of 2500 F. The reactions occurring in conversiontube E produce a considerable amount of heat, loss of which is preventedin the apparatus described by the heat retentive wall i4 and bottominsulating bricks 8.

In order to cool or quench this equilibrium mixture substantiallyinstantaneously, the conversion products are passed through conduits I9into annular chamber 2l and without substantial reduction of temperatureare introduced into the bottom of gas cooling tubes 24 where they arequickly cooled so as to pass from the heat exchange tubes at atemperature of about 900 F. The pressure of the exit gases will besubstantially the pressure in the conversion tube i. e. about 300 poundsper square inch.

The apparatus disclosed is effective to prevent any premature cooling ofthe conversion products because the loss of heat by radiation to thequench cooler is substantially completely avoided. Thus, the onlyconversion gases which are in a position to radiate heat to the quenchcooler are the gases contained in chamber 2| and these gases almostimmediately pass into the heat exchange tubes. There is substantially noreduction of temperature of the conversion gases until they enter thegas cooling tubes 24.

Due to the structure of the quench cooler, and particularly the factthat the hot gases pass through the parallel gas cooling tubes 24 whichare in contact with water acting as a cooling medium, substantiallyinstantaneous cooling is accomplished which is effective to stabilizeand iix the composition of the conversion products at the compositionattained at the elevated conversion temperature of 2500 F.

The cooling medium employed is preferably water which, depending uponthe plant requirements, is converted into high or low pressure steam.

It will be seen that the apparatus disclosed has the important advantagein addition to that of permitting a substantially instantaneous quenchcooling of the conversion products of providing means for protecting theconversion zone from excessive cooling.

It will be recognized by those skilled in the art that the apparatusdisclosed in the drawing can be modified in many ways within the scopeof the invention. For example, the position of entering and exitconduits may be the reverse of that shown; i. e. the unit may be ineffect inverted. In such case, the flow of gases through the conversiontube and the quench cooler will be in the opposite direction from thatdescribed. 'While it is important when carrying out extremelyhightemperature reactions and using water as the cooling medium that thehot gases flow upwardly through the quench cooler, satisfactory resultsare obtained when carrying out lower-temperature reactions, particularlywhen using a different cooling medium, by causing the hot gases to flowdownwardly through the quench cooler.

Obviously many modifications and variations of the invention ashereinabove set forth may be made without departing from the spirit andscope thereof and therefore only such limitations should be imposed asare indicated in the appended claim.`

I claim:

An apparatus for producing synthesis gas by conversion of hydrocarbonswhich comprises in combination in a pressure-tight vessel, an elongatedconversion tube centrally and axially 1ocated in said vessel, closed atits upper and lower ends and insulated over substantially all of itsinner surface by insulating heat retentive walls, said elongatedconversion tube containing at least one inlet conduit at the top thereofextending from without the said vessel and a plurality of slots disposedin the bottom of and extending through the side wall of said conversiontube, cooling means comprising a lower tube sheet, a water wall beneathsaidlower tube sheet and surrounded by the lower portion of saidpressuretight vessel, vertical heat exchange tubes open at each end, anupper tube sheet, and a heat exchange chamber, said cooling meanssurround'- ing said conversion tube within said reaction vessel with itssaid lower tube sheet positioned at a higher vertical point 'than butimmediately adjacent to said slots, and an annular chamber surroundingsaid conversion tube'closed at the lower end by an insulating heatretentive wall and bounded also by the insulating heat retentive sidewall of the lower end of said conversion tube containing said slots, bysaid water wall, and by said lower tube sheet, said annular chamberbeing in communication with the interior of said conversion tube bymeans of said slots and with said heat exchange tubes, whereby hotreaction gases formed in said conversion tube flow downwardly throughsaid conversion tube while they are maintained at an elevatedequilibrium temperature by said insulating heat retentive walls of saidconversion tube and pass from said conversion tube through said slots tosaid annular chamber while avoiding any substantial transfer of heat byradiation from said conversion tube to said cooling means and then flowupwardly through said cooling means.

CLARENCE L. CRAWFORD.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS

